Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Pulsatility index (PI) in the middle cerebral artery (MCA) is considered a measure of peripheral vascular resistance. Several established cardiovascular risk factors are common for both MCA PI and carotid atherosclerosis. Accordingly, in the present study we hypothesized an association between ultrasound-derived indices of carotid atherosclerosis and MCA PI. ⋯ In a population-based sample of middle-aged adults, ultrasound-derived indices of carotid atherosclerosis were independently associated with MCA PI. However, the overall explained variance of MCA PI was low, suggesting other factors than atherosclerosis and cardiovascular risk factors to play an important role for MCA PI.
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In the setting of an extended time window for endovascular treatment (EVT) for acute stroke patients, computed tomography perfusion (CTP) has become a major tool in patient selection. However, there are some data suggesting that the initial ischemic core may be overestimated by CTP depending on stroke onset time. This study aims to evaluate possible predictors of overestimation of infarct core by CTP. ⋯ Over estimation of the infarct core by CTP in patients undergoing EVT is time dependent and so CTP results among early arrivers should be interpreted cautiously.
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Comparative Study
Noncontrast CT versus Perfusion-Based Core Estimation in Large Vessel Occlusion: The Blood Pressure after Endovascular Stroke Therapy Study.
The 2018 AHA guidelines recommend perfusion imaging to select patients with acute large vessel occlusion (LVO) for thrombectomy in the extended window. However, the relationship between noncontrast CT and CT perfusion imaging has not been sufficiently characterized >6 hours after last known normal (LKN). ⋯ In this multicenter prospective cohort of patients who underwent thrombectomy, one-third of patients had normal CTP core volumes despite nearly three quarters of patients showing ischemic changes on CT. This finding emphasizes the need to carefully assess both noncontrast and perfusion imaging when considering thrombectomy eligibility.
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Corpus callosum atrophy is a neurodegenerative biomarker in multiple sclerosis (MS). Manual delineations are gold standard but subjective and labor intensive. Novel automated methods are promising but require validation. We aimed to compare the robustness of manual versus automatic corpus callosum segmentations based on FreeSurfer. ⋯ FreeSurfer's longitudinal stream provides corpus callosum measures with better repeatability than current manual methods and with similar clinical correlations. However, due to some limitations in accuracy, caution is warranted when using FreeSurfer with clinical data.
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Functional magnetic resonance imaging (fMRI) is becoming widely recognized as a key component of preoperative neurosurgical planning, although intraoperative electrocortical stimulation (ECS) is considered the gold standard surgical brain mapping method. However, acquiring and interpreting ECS results can sometimes be challenging. This retrospective study assesses whether intraoperative availability of fMRI impacted surgical decision-making when ECS was problematic or unobtainable. ⋯ Preoperative fMRI allowed for continuation of surgery in over one-fourth of patients in which planned ECS was incomplete or impossible, without a significantly different incidence of postoperative deficits compared to the patients with completed ECS. This demonstrates additional value of fMRI beyond presurgical planning, as fMRI data served as a backup method to ECS.